RNA-Seq analysis and de novo transcriptome assembly of Cry toxin susceptible and tolerant Achaea janata larvae

Abstract

Larvae of most lepidopteran insect species are known to be voracious feeders and important agricultural pests throughout the world. Achaea janata larvae cause serious damage to Ricinus communis (Castor) in India resulting in significant economic losses. Microbial insecticides based on crystalline (Cry) toxins of Bacillus thuringiensis (Bt) have been effective against the pest. Excessive and indiscriminate use of Bt - based biopesticides could be counter-productive and allow susceptible larvae to eventually develop resistance. Further, lack of adequate genome and transcriptome information for the pest limit our ability to determine the molecular mechanisms of altered physiological responses in Bt-exposed susceptible and tolerant insect strains. In order to facilitate biological, biochemical and molecular research of the pest species that would enable more efficient biocontrol, we report the midgut de novo transcriptome assembly and clustering of susceptible Cry toxin-exposed and Cry toxin tolerant Achaea janata larvae with appropriate age-matched and starvation controls.

Which Is Stronger? A Continuing Battle Between Cry Toxins and Insects

“…Second, it is also urgent to thoroughly investigate the insect resistance mechanisms, especially on the applications of various high-throughput sequencing technologies and multiomics techniques (e.g., transcriptomic, proteomics, metabonomics, and epigenomics), to enrich the database of insecticidal proteins or rapidly screen the vital resistance genes ( Dhania et al, 2019 ). By artificially selecting new types of resistant insects in the laboratory, one can foresee farther the possible resistant pathways of insects; in the same token, scientists can also use control strategies for insect resistance issue purposefully, such as the use of genetic engineering, synthetic biology, and other technologies ( Vílchez, 2020 ) to carry out a directed evolution of Cry toxins by constructing various Cry mutants for enhancing its virulence, or expanding its insecticidal spectrum; or, for targeting insects, by using CRISPR/Cas9-based gene manipulation technology to restore resistant mutants back to the wild type ( Esvelt et al, 2014 ), as well as using the mating and reproduction characteristics of insects to reduce the number of resistant populations.…”

“…Second, it is also urgent to thoroughly investigate the insect resistance mechanisms, especially on the applications of various high-throughput sequencing technologies and multiomics techniques (e.g., transcriptomic, proteomics, metabonomics, and epigenomics), to enrich the database of insecticidal proteins or rapidly screen the vital resistance genes (Dhania et al, 2019).…”